VLC is a capable video converter for one-off jobs, and together with two other free tools it handles almost every video conversion task: VLC for quick one-off conversions with no extra software, FFmpeg for fast lossless remuxing and batch automation from the command line, and HandBrake for quality-controlled re-encoding with presets for every device.
For quick conversions without installing anything, our online video converter handles the common formats (for example MKV to MP4) — you upload from any browser and the conversion runs on our servers. The desktop tools below are better for large files, batch jobs, or regular conversion work.
VLC Video Converter: Quick Conversions Without Extra Software
VLC is primarily a media player, but its built-in converter handles most common format changes without installing additional software.
How to convert video with VLC
- Open VLC → Media → Convert/Save (Ctrl+R on Windows)
- Click Add and select your video file
- Click the Convert/Save button
- In the Profile dropdown, choose your target format:
- Video — H.264 + MP3 (MP4) — universal MP4
- Video — H.265 + MP3 (MP4) — smaller files, modern devices
- Audio — MP3 — audio only
- Set the destination file path (include the correct extension)
- Click Start
VLC re-encodes by default, which takes longer than remuxing — on a long video, expect it to run for a good while, depending on your CPU and settings. The profile editor (wrench icon) has "Keep original video track" and "Keep original audio track" options for a copy without re-encoding, but results vary by container; FFmpeg is the more reliable tool for that.
Extract MP3 audio from video with VLC
Use the same Convert/Save dialog but select the Audio — MP3 profile. VLC drops the video stream and encodes only the audio. This is useful for extracting a soundtrack, podcast recording, or voiceover from a video file.
Convert Video with FFmpeg: Fast, Lossless, Scriptable
FFmpeg is a command-line tool that runs on Windows, Mac, and Linux. It's faster than VLC for most tasks because it can remux — move video streams between containers without re-encoding.
Install FFmpeg
- Mac: brew install ffmpeg
- Windows: download from ffmpeg.org, extract, add to PATH
- Linux: sudo apt install ffmpeg
MKV to MP4 (lossless remux)
ffmpeg -i input.mkv -c copy output.mp4
The -c copy flag copies all streams without re-encoding, so even a multi-gigabyte MKV finishes about as fast as your disk can copy it. Use this whenever the MKV contains H.264 or H.265 video — it's lossless and instant.
MKV to MP4 with audio re-encode
ffmpeg -i input.mkv -c:v copy -c:a aac output.mp4
If the MKV contains FLAC or DTS audio (not supported in MP4), add -c:a aac to re-encode only the audio.
Video is still copied losslessly.
Extract MP3 audio from video
ffmpeg -i video.mp4 -q:a 0 -map a audio.mp3
-q:a 0 uses variable bitrate at highest quality. -map a selects only the audio stream. Works with MP4, MKV, MOV, AVI — any format FFmpeg can read.
Convert MP4A / MPEG-4 Audio to MP3
"mp4a" is the codec tag players show for AAC audio in MP4-family files; audio-only files of this kind use the .m4a extension:
ffmpeg -i audio.m4a -codec:a libmp3lame -q:a 2 output.mp3
-q:a 2 is approximately 190 kbps variable bitrate — excellent quality. For our online converter, use the M4A to MP3 tool directly.
Batch convert a folder
Mac/Linux — convert all MKV files in the current folder to MP4:
for f in *.mkv; do ffmpeg -i "$f" -c copy "${f%.mkv}.mp4"; done
Windows PowerShell:
Get-ChildItem *.mkv | ForEach-Object { ffmpeg -i $_.Name -c copy ($_.BaseName + ".mp4") }
Convert Video with HandBrake: Quality Encoding with Presets
HandBrake is the best free GUI tool when you need to compress video while controlling quality — converting a 4K file for a tablet, shrinking a large video for sharing, or preparing content for specific devices.
- Open HandBrake and drag your video onto the window
- Choose a Preset from the right panel (Fast 1080p30 is a good default for general use; device-specific presets like Apple TV or Android are in the sub-menus)
- Set the output folder in the Save As field
- Click Start Encode — or Add to Queue for batch processing
HandBrake always re-encodes, which takes longer than FFmpeg remuxing but gives you control over the output size and quality.
Which Free Video Converter to Use
| Task | Best tool | Speed |
|---|---|---|
| MKV → MP4, no quality change | FFmpeg -c copy | Seconds |
| Single file conversion, no CLI | VLC or online tool | Minutes |
| Compress video for sharing/storage | HandBrake | Minutes–hours |
| Batch convert a folder | FFmpeg loop or HandBrake queue | Varies |
| Extract audio from video | FFmpeg or online tool | Seconds |
Summary
Use FFmpeg with -c copy for instant lossless remuxing (MKV → MP4 in seconds), HandBrake when you need quality-controlled re-encoding with presets, and VLC for occasional one-off conversions without installing anything new. For jobs without installing anything, the online video converter covers the common formats.
Related Tools
- MKV to MP4 guide — format comparison and conversion options
- Extract audio from video — de-mux vs re-encode, VLC and FFmpeg recipes
- AVI to MP4 — convert old Windows video format
- Video to MP3 converter — online audio extraction, no software needed